Well water

[Paul Rust]

The main reason you don't want to use hard water for misting is because of the deposits left on glass. As long as the water is not ridiculously hard it is unlikely to cause a health issue with the frogs. My well water is fairly hard too and it has never caused my frogs a problem that I am aware of.

Same here.
The only difference with me is I use distilled or R/O water in my auto misters because the tiny nozzles create 10 micron droplets that Ca and Mg will clog. Otherwise I hand mist with well water and use it in my water features with no problems.